I remember that bass. It sold on the bay a short while back. Originally from a music store, I think. That strap button on the back is what I recognize. Lemmy style!
The balance would be terrible! Your left arm would be pretty tired after holding that bass up all night. My 4000 is quite neck heavy & it requires a different technique to play for extended periods.
There's a very good reason the strap button is on the end of the upper horn.